Cap 5-11 cm broad, convex, broadly convex in age; margin at first incurved, decurved at maturity; surface viscid when moist, pale yellow to dingy-buff, tomentose, becoming squamose, occasionally weathering to nearly smooth; scales typically greyish to olive-grey, sometimes reddish in cold weather; flesh thick, soft, white to pale yellow, bluing slowly when injured; odor, mild to fruity/harsh; taste mild.
Tubes up to 1.5 cm long, dingy yellowish-olive, slowly bluing when cut, adnate to depressed at the stipe; pores approximately 1/mm, angular, dull brown, becoming dingy ochre at maturity, bluing slowly when bruised.
Stipe 5-9 cm. long, 1.5-3.0 cm thick, solid, equal or enlarged at the base; surface sticky, yellowish to apricot-orange at the apex, sometimes tinged dull reddish-brown at the base, dotted with brown glandulae; context like the cap, i.e. pallid to pale yellow, usually bruising blue slowly; veil absent.
Spores 8-11 x 3-4 µm, narrowly elliptical to subfusiform, smooth, thin-walled; spore print dark olive-brown.
Scattered or in small groups under pines; fruiting from after the fall rains to mid-winter.
Edible, but soft-textured.
Suillus tomentosus is found along the coast north of San Francisco, usually with beach pine (Pinus contorta). It is characterized by a viscid, when moist, dull yellowish to dingy-buff cap, covered with greyish to greyish-olive squamules which sometimes redden in cold weather, and a tendency to bruise blue slowly when injured. Similar species in our area include Suillus fuscotomentosus which has darker scales, does not bruise blue, usually associated with Ponderosa pine, and Suillus acerbus, seldom as scaly, and typically more apricot-brown in color. It additionally has larger, more conspicuous stipe glands, does not bruise blue, and fruits under Monterey pine.